As a conventional membrane separator, for example, a submerged membrane filtration apparatus having a plurality of membrane elements arranged in parallel at appropriate intervals is known.
For example, in a membrane separator described in Japanese Patent Application Laid-Open No. H11-33370, two flat membranes are stacked via a spacer, the two flat membranes are welded or bonded end to end on both sides of the two flat membranes to form a filtration membrane member, and filtration water collecting portions provided on the sides of the filtration membrane member communicate with the inside of the filtration membrane member.
In a membrane separator described in Japanese Patent No. 3815645, a separator unit is mounted with filtration membranes on both surfaces of a water passing material having a water passing function, the membrane ends of the filtration membranes are joined to the water passing material with joining members, hollow portions are formed in the joining members, and suction pipes provided in the hollow portions of the joining members communicate with the channel of the water passing material.
The conceptual model of such a membrane separator is shown in FIGS. 18 to 19. A plurality of membrane elements 1 are arranged in parallel and channels 2 are formed along the flowing direction of a liquid to be treated between the membrane elements 1. The membrane elements 1 are formed by arranging filtration membranes on the surfaces of membrane supporting members and have permeate channels between the membrane supporting members and the filtration membranes. Water collecting cases 3 arranged on both sides of the membrane elements 1 have opening portions communicating with water collecting spaces 4 in the water collecting cases 3. The sides of the membrane elements 1 inserted in the opening portions are held water-tight by sealing materials. The permeate channels of the membrane elements 1 communicate with the water collecting spaces 4 of the water collecting cases 3.